code: def x_dist(x_s, x_t):
      dx = x_t - x_s
      return dx
  
file_path: deepgraph/doc/source/tutorials/10min_to_deepgraph.py
imports: import matplotlib.pyplot
  import numpy
  import pandas
  import deepgraph
label_desc: Use image node_id 1 for calling a global function with example usage: x_dist(x_s, x_t) and returns: dx